JP3293698B2 - Array waveguide diffraction grating type optical multiplexer / demultiplexer with loopback optical path - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitably used in an optical transmission system, an optical switching system, etc., and has a simple structure, high stability, and a good yield, and an array waveguide with a loop-back optical path. The present invention relates to a diffraction grating type multiplexer / demultiplexer.

[0002]

2. Description of the Related Art Conventionally, an optical add-drop multiplexer (ADM) as shown in FIG. 19 has been known as a key device used for dropping / inserting a wavelength multiplexed optical signal. This optical add / drop circuit 1 includes a duplexer 2 and
It is composed of a multiplexer 3 and N optical fibers 4a, 4b,..., 4n. In the optical ADM circuit 1, the multiplexed optical signal having the wavelengths λ1, λ2,..., ΛN is separated into signal light having N wavelengths by the demultiplexer 1, and the necessary signal light, for example, the wavelength λi, λj The signal light is taken out. The remaining signal light propagates through the optical fibers 4a, 4b,.
The multiplexer 2 multiplexes these signal lights and signal lights of wavelengths λi, λj inserted from the outside, and outputs the wavelengths λ1, λ2,.
Are output as multiplexed optical signals.

An optical add / drop circuit as shown in FIG. 20 is also known. The optical add / drop circuit 5 is provided between the optical fiber transmission lines 6 and 7, and includes a demultiplexer 11, a multiplexer 12, and seven optical fibers 13a, 13b,.
3g and a signal processing device 14 provided in each of the optical fibers 13a to 13g. In general, the number of multiplexed wavelengths is arbitrary, but here, seven waves are used for simplicity. In this optical add / drop circuit 5, the incident wavelength λ
The multiplexed optical signal of 1, .lambda.2,..., .Lambda.7 is separated into signal lights of seven wavelengths by the demultiplexer 11, and these signal lights are propagated through the optical fibers 13a to 13g corresponding to each wavelength. The separated signal lights are respectively sent to the signal processing devices 14, 1
The transmitted information can be obtained by being converted into an electric signal by 4,... And taken out to the outside. A reply to this information or information to be newly transmitted is converted into signal light by the signal processing device 14 and input to the optical fiber 13 corresponding to this signal light. In the multiplexer 12,
Each of the signal lights propagated through the optical fibers 13a to 13g is multiplexed and output as a multiplexed optical signal having wavelengths λ1, λ2,.

In the optical add / drop circuit 5, signal processing is performed for all wavelengths, but generally, signal processing is rarely performed for all wavelengths. In such a case, the optical fiber 13 is used for a wavelength for which no signal processing is performed.
Only, the signal processing device 14 can be omitted.

There is also known a variable optical delay line memory for storing optical pulses with a desired time delay. The variable optical delay line memories are roughly classified into a tap type typified by a parallel arrangement type and a loop type typified by a loop delay type according to the operation principle. FIG. 21 is a configuration diagram showing a parallel arrangement type optical delay line memory. This optical delay line memory 21
Is a fixed wavelength light source 22, a 1 × N optical coupler 23 for branching an optical signal pulse from the fixed wavelength light source 22, and a different length, that is, a different time delay amount iτ (i = 1) according to the transmission path of the optical signal. , 2,..., N) and a plurality of delay optical fibers 24a, 24b,.
N selects one of the optical signal pulses given τ
It comprises a × 1 optical switch 25 and a photodetector 26 for converting the output optical signal pulse into an electric signal. The optical delay line memory 21 has an advantage that the variation in optical loss in a plurality of transmission paths is small.

FIG. 22 is a block diagram showing a loop-type optical delay line memory. This optical delay line memory 31
A fixed wavelength light source 22, a 2 × 2 optical coupler 32, a delay optical fiber 33 forming a loop, and an optical amplifier 34
, An optical switch 35, and a photodetector 26. In the optical delay line memory 31, the fixed wavelength light source 22
The optical signal pulse output from the optical fiber is input into the loop around which the delay optical fiber 33 is provided via the 2 × 2 optical coupler 32. In this loop, the time delay amount when this optical signal pulse makes i rounds is iτ (i = 1, 2,...,
N). The optical pulse having a desired time delay passes through the optical switch 35 by the gate function of the optical switch 35, is received by the photodetector 26, and is converted into an electric signal. Here, the optical power of the optical pulse input to the 2 × 2 optical coupler 32 drops in principle by ４ when it makes one round in the loop and passes through the 2 × 2 optical coupler 32 again in principle. When the loop has made N rounds, it drops to 1/2 ^{N + 1} . Therefore, the optical loss is compensated for by using the optical amplifier 34. The optical delay line memory 31 has an advantage that the scale of hardware is small because the optical delay line memory 31 is circulated by a loop.

On the other hand, an arrayed waveguide grating type optical multiplexer / demultiplexer as shown in FIG. 23 has been proposed as a key device for constructing a lightwave address network, an optical switching system, and the like. The arrayed waveguide grating type optical multiplexer / demultiplexer 41 includes N input waveguides 4 on a substrate 42.
3, provided with concave slab waveguides 44, 45, an arrayed waveguide diffraction grating 46, and N output waveguides 47, and wavelengths λ1, λ2,.
The multiplexed signal light of λn is separated into signal lights of N wavelengths and output waveguides 47j (j = a, b,...) corresponding to each wavelength λi.
n).

[0008]

In the above-described optical add / drop circuit 1, since the duplexer 2 and the multiplexer 3 are used as a pair, the demultiplexing characteristic of the duplexer 2 and It is necessary to strictly match the multiplexing characteristics of the multiplexer 3, but it is extremely difficult to match these characteristics with high accuracy in terms of manufacturing technology, which significantly reduces the yield and is a major factor in cost increase. There was a problem of becoming. Also, in the optical add / drop circuit 5, similarly to the optical add / drop circuit 1, since the wavelength characteristics of the demultiplexer 11 and the multiplexer 12 need to be completely matched, the demultiplexing with the matched wavelength characteristics is performed. It is necessary to select the device 11 and the multiplexer 12, and there is a disadvantage that the yield is low. Further, the configuration of the optical add / drop circuit 5 has a disadvantage that the scale is increased.

In the optical delay line memory 21 described above, 1
Since the × N optical coupler 23 and the N × 1 optical switch 25 are used, the optical switch 25 and the optical coupler 23 having the same optical loss and optical branching ratio are indispensable, and the number of components and the number of optical fiber connection steps increase. There were major drawbacks. Therefore, the number of optical components constituting the hardware increases, and there is a problem in economy. Further, when the number of branches (N) becomes large, there is another problem that it is particularly difficult to realize the N × 1 optical switch 25 for switching the optical signal pulse delay amount. In the optical delay line memory 31 described above,
Since the loop gain cannot be set to 1, the optical loss increases as the number of rounds of the optical pulse increases.
Since the light passes through the optical amplifier 14 a plurality of times, spontaneous emission noise accumulates and the S / N ratio deteriorates.

In the above-mentioned array waveguide diffraction grating type optical multiplexer / demultiplexer 41, the multiplexed signal light having the wavelengths λ1, λ2,..., ΛN is separated into N wavelength signal lights, and the output corresponding to each wavelength λi is output. Although it is possible to output the light from the waveguide 47j, it cannot be said that the unused input waveguide 43 and the output waveguide 47 are used sufficiently because of the large number of unused input waveguides 43 and output waveguides 47. Is not fully utilized.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a simple structure, and can improve the yield and achieve high stability. It is to provide a duplexer.

[0012]

In order to solve the above-mentioned problems, the present invention employs the following arrayed waveguide diffraction grating type multiplexer / demultiplexer with a loop-back optical path. In other words, the array waveguide diffraction grating type multiplexer / demultiplexer with a loopback optical path according to the first aspect of the present invention provides a loop used for demultiplexing and multiplexing wavelength multiplexed signal light.
An array waveguide diffraction grating type optical multiplexer / demultiplexer with a
Therefore, an arrayed waveguide grating type optical multiplexer / demultiplexer and a plurality of
An array waveguide diffraction grating , comprising:
Type optical multiplexer / demultiplexer has an arrayed waveguide diffraction grating and signal light
A plurality of input sections for inputting a signal light,
A plurality of output units as many as the number of input units, and the plurality of input units
And an optical signal provided between the array waveguide diffraction grating and
A first slab waveguide for demultiplexing or multiplexing;
Light provided between an output section and the arrayed waveguide diffraction grating;
A second slab waveguide for splitting or combining a signal.
And, wherein one of the plurality of input unit input signal from the outside
An input section for inputting light; and a plurality of output sections.
One of them is an output section for outputting an output signal light to the outside.
The plurality of loopback optical paths are connected to the output signal to the outside.
A plurality of the output units except an output unit for outputting light,
Multiple fronts except for the input section to input the input signal light from outside
Between the input section and the input section.
An output for outputting an output signal light to the outside of the number of output units
Signal light from each output unit except for the plurality of
An input for inputting an input signal light from the outside of the input unit
Connected so as to input to the input portion except the parts, the double
At least one of the number of loopback paths
Signal that performs signal processing on signal light propagating in the loopback optical path
Signal multiplexing means provided from outside
The signal light is converted by the array waveguide diffraction grating type optical multiplexer / demultiplexer.
Demultiplex, and loop back these multiple demultiplexed signal lights.
The array waveguide diffraction grating type optical multiplexing / demultiplexing through the optical path again
And combine them to output to the outside as output signal light.
It is characterized by being configured so that.

[0013]

[0014]

Further, the loop-back optical path with an array waveguide diffraction grating type demultiplexer of claim 2, in loop-back optical path with an array waveguide diffraction grating multiplexer-demultiplexer of claim 1, wherein said array guide It is characterized in that a waveguide grating type optical multiplexer / demultiplexer and a plurality of the loopback optical paths are integrated.

An array waveguide diffraction grating type multiplexer / demultiplexer with a loopback optical path according to a third aspect of the present invention is the first or second aspect.
In the arrayed-waveguide grating optical multiplexer / demultiplexer with a loop-back optical path described in the above, the pilot signal light of the signal light does not pass through the loop-back optical path, and an input signal from the outside.
Array waveguide diffraction from the input section for inputting signal light
Input to grating type optical multiplexer / demultiplexer and output signal light to outside
And outputting the data from the output unit .

An array waveguide diffraction grating type multiplexer / demultiplexer with a loop-back optical path according to a fourth aspect of the present invention is further characterized in that :
4. In the arrayed-waveguide grating optical multiplexer / demultiplexer with a loop-back optical path described in 3 , the loop-back optical path is a delay unit.

[0018]

The array waveguide diffraction grating type multiplexer / demultiplexer with a loop-back optical path according to the first aspect of the present invention provides an array waveguide diffraction.
Equipped with a grating type optical multiplexer / demultiplexer and a plurality of loopback optical paths
The array waveguide diffraction grating type optical multiplexer / demultiplexer includes an array
A waveguide diffraction grating and a plurality of input portions to which signal light is input
Signal light is output and the same number of multiple
A number of outputs, the plurality of inputs and the array waveguide circuit.
A second splitter or splitter for optical signals provided between
One slab waveguide, the plurality of outputs, and the array conductor.
Separates or combines optical signal provided between waveguide grating
A second slab waveguide, and
One of them is an input for inputting an input signal light from outside.
One of the plurality of output units is connected to the outside.
An output unit for outputting a force signal light;
The optical path includes an output section for outputting the output signal light to the outside.
A plurality of the output units, and input signal light from the outside.
Each of the plurality of input units except for the input unit
Correspondingly, and the outside of the plurality of output units.
Output from each output unit except the output unit that outputs the output signal light to the
The signal light is transmitted to the outside of the corresponding one of the plurality of input units.
Input to each input section except the input section that inputs the input signal light from the
Connected to the plurality of loopback light paths.
At least one of them propagates through this loopback path
Signal processing means for performing signal processing on the signal light to be provided,
The wavelength multiplexed signal light input from the outside is guided into the array waveguide.
Demultiplexed by a path grating optical multiplexer / demultiplexer.
A plurality of signal lights are again transmitted through each loopback optical path.
Ray-waveguide grating type optical multiplexer / demultiplexer
Since it is configured to output the output signal light to the outside, the demultiplexing operation and the multiplexing operation are performed by the same optical multiplexer / demultiplexer. Therefore, the wavelength characteristics of the demultiplexer and the multiplexer are completely matched, and the production yield is improved. Further, since the signal light passes through the optical multiplexer / demultiplexer having the same characteristic a plurality of times, the pass band of the signal light becomes narrower, and therefore, the noise spectrum component of the optical signal spectrum is greatly reduced.

Further , among the plurality of loopback optical paths,
By providing at least one of the signal processing means for performing signal processing on the signal light propagating through the loopback optical path, it is possible to separately perform signal processing required for the optical signal for each wavelength. .

[0020]

According to a second aspect of the present invention, there is provided an arrayed waveguide grating type multiplexer / demultiplexer with a loopback optical path, wherein the arrayed waveguide grating type optical multiplexer / demultiplexer is integrated with a plurality of the loopback optical paths. As a result, the coupling loss between the arrayed waveguide grating type optical multiplexer / demultiplexer and the plurality of loopback optical paths is reduced, thereby realizing a small and stable arrayed waveguide grating type multiplexer / demultiplexer with a loopback optical path. Becomes possible.

In the array waveguide grating type multiplexer / demultiplexer with a loop-back optical path according to a third aspect of the present invention, the pilot signal light of the signal light does not pass through the loop-back optical path, and an input signal from the outside. From the input section to input light
Input to the array waveguide diffraction grating type optical multiplexer / demultiplexer,
With the configuration in which the output signal light is output from the output unit , the pilot signal light is used as a reference signal to stabilize each signal light.

Further, in the array waveguide diffraction grating type multiplexer / demultiplexer with a loop-back optical path according to the fourth aspect , the loop-back optical path is a delay means, so that the position on the time axis with respect to the time-series optical pulse. Control. Therefore, it is possible to perform control and accumulation (memory operation) such as compression and separation on the time axis for the time-series optical pulse group.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an arrayed waveguide grating type multiplexer / demultiplexer with a loop-back optical path according to the present invention will be described below in detail with reference to the drawings. (Embodiment 1) FIG. 1 is a configuration diagram showing an arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path according to Embodiment 1 of the present invention. This arrayed waveguide grating type optical multiplexer / demultiplexer with a loopback optical path is provided with an arrayed waveguide grating type optical multiplexer / demultiplexer 41 between optical fiber transmission lines 6 and 7, and each output waveguide 47 and input waveguide 43, an optical fiber (loopback optical path) 51 for inputting signal light output from the output waveguide 47 to the input waveguide 43 corresponding to the output waveguide 47 is provided. 51 is provided with a signal processing device 52. Here, the optical fiber transmission line 6 has eight input waveguides 43a to 43a.
3h, which is connected to the input waveguide 43h,
Similarly, the optical fiber transmission line 7 includes eight output waveguides 47a to 47e.
The output waveguide 47h is connected to one of the output waveguides 47h.

In this arrayed-waveguide grating multiplexer / demultiplexer with a loop-back optical path, seven wavelength-multiplexed optical signals having wavelengths λ 1, λ 2,..., Λ 7 are propagated through the optical fiber transmission line 6. The signal is input to the input waveguide 43h of the arrayed waveguide grating type optical multiplexer / demultiplexer 41. In the slab waveguide 44, the wavelength multiplexed optical signal spreads by diffraction, and is input to a plurality of waveguides forming an arrayed waveguide diffraction grating 46. The signal light is condensed by the slab waveguide 45 after propagating through the arrayed waveguide diffraction grating 46.
The focused position of the focused light differs depending on the wavelength due to the phase difference generated while propagating the light. For example, wavelength λ1 is from output waveguide 47a, wavelength λ2 is from output waveguide 47b,
.., The wavelength λ7 is from the output waveguide 47g, and the wavelength λi is the corresponding output waveguide 47j (j = a, b,.
g). That is, it is split. Thereafter, each of the demultiplexed signal lights is transmitted to the corresponding optical fiber 51.
The light propagates through a through 51g and is guided to signal processing devices 52a through 52g.

The signal processor 52 receives the signal light and obtains the transmitted information. Each signal processing device 52a-
52g has a built-in light source for generating light having the same wavelength as the received wavelength, the information to be transmitted is placed on the signal light, and the optical waveguide 51 again passes through the arrayed waveguide grating type optical multiplexer / demultiplexer. It is returned to 41. The signal light input again into the input waveguide 43 is multiplexed into the output waveguide 47h by the same operation as the first time. What is important here is that the j-th optical fiber 51j is connected to the j-th input waveguide 43j. Wavelength λ input from input waveguide 43j
The signal light of i is output from the output waveguide 47h. That is, the signal lights of all the wavelengths λ1, λ2,..., Λ7 are sent from the output waveguide 47h to the optical fiber transmission line 7.
On the other hand, of the signal light, the pilot signal light of wavelength λ0 does not pass through the optical fiber 51 and the signal processing device 52,
The light is output via each of the input waveguide 43h, the arrayed waveguide diffraction grating 46, and the output waveguide 47h.

As described above, the arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with a loop-back optical path of the present embodiment uses the loop-back optical path of returning the demultiplexed output light to the input side by using the optical fiber 51. With a clever configuration, multiplexing and demultiplexing can be performed by one arrayed waveguide grating optical multiplexer / demultiplexer 41.

In this embodiment, the signal processing device 52 is connected to all the optical fibers 51 so as to perform signal processing on all seven wavelengths. Of the wavelength multiplexed optical signals to be processed, signal processing is often performed only on signal light of a specific wavelength. In this case, since the signal processing device 52 is unnecessary in the optical fiber 51 through which the signal light having the wavelength not subjected to the signal processing propagates, the signal processing device 52 may be removed.

Next, the signal processing device 52 used in this embodiment will be described in detail with reference to FIG. FIG.
The signal processing device shown in (a) is an optical pulse reproduction processing device, which is composed of a photodiode and a control circuit including the photodiode.
/ E converter 53, an E / O converter 54 comprising a semiconductor laser and its control circuit, and an optical pulse which is provided between the O / E converter 53 and the E / O converter 54 and becomes dull due to transmission. And a waveform shaping circuit (not shown) for shaping the waveform. This waveform shaping circuit has a function of newly generating a rectangular pulse having the same bit rate based on an electrically dull pulse. An optical signal having information to be received is converted into an electric signal by the O / E converter 53 and extracted from an electric signal output 55. The information to be transmitted is input from the electric signal input 56 as an electric signal, and E /
The optical fiber 51 is converted into an optical signal by the O
(Or an optical waveguide).

The signal processing device shown in FIG. 2B includes an optical amplifier 57 such as a glass waveguide amplifier, an optical semiconductor amplifier, and an erbium-doped optical fiber amplifier.
This makes it possible to compensate for the intensity of light weakened while propagating through the optical fiber transmission line 6 and the arrayed waveguide diffraction grating 46.

FIG. 2C shows an example in which the signal processing device 52 is connected to the optical fiber 51 using a 2 × 2 optical switch 58. The optical switch 58 is made of quartz glass, an optical semiconductor, a lithium niobate optical waveguide, or the like.
It consists of a x2 Mach-Zehnder interferometer and has four ports 61-64. In the optical switch 58, when the switch is in the through state, the ports 61 and 63 are not connected.
The port 62 and the port 64 are connected, and the signal light passes without signal processing. On the other hand, when the switch is set to the cross state, the ports 61 and 64 and the ports 62 and 63 are connected to perform signal processing.

The signal processing device shown in FIG. 2D has an optical filter 65 using a waveguide type ring resonator having wavelength selectivity, a waveguide type Mach-Zehnder interferometer, a dielectric multilayer film (interference film) or the like. It consists of. If a higher resolution arrayed waveguide grating optical multiplexer / demultiplexer is used, the optical signal can be multiplexed / demultiplexed with higher accuracy. When this arrayed waveguide grating optical multiplexer / demultiplexer is used, branching and insertion of optical frequency multiplexed light becomes possible.

In this embodiment, of the plurality of input waveguides 43 and output waveguides 47, the optical fiber transmission line 6 is connected to the end input waveguide 43h and the end is set to the output waveguide 47h. Although the optical fiber transmission lines 7 are respectively connected, the present embodiment is not limited to this. For example, the optical fiber transmission line 6 is connected to the input waveguide 43b, and the output waveguide 47 is connected to the input waveguide 43b.
The same operation and effect can be obtained by a configuration in which the optical fiber transmission lines 7 are connected to b. Generally, the array waveguide diffraction grating type optical multiplexer / demultiplexer 41 has the highest diffraction efficiency and low loss when the input waveguide 43 and the output waveguide 47 located at the center are used. Therefore, the optical fiber transmission line 6
The input waveguide 43d near the center (or the input waveguide 43)
In e), it is more efficient to connect the optical fiber transmission line 7 to the output waveguide 47d (or the output waveguide 47e) near the center.

In the present embodiment, the number of multiplexed wavelengths of the arrayed waveguide grating type optical multiplexer / demultiplexer 41 is set to 8, but the embodiment is not limited to this. If the design is changed, the number of multiplexed wavelengths can be easily changed. In addition, the signal processing device 52 is a 2 × 2
Optical coupler. In this case, of the two optical signals branched by the optical coupler, one optical signal propagates through the optical fiber 51, and at the same time, the other optical signal is extracted to the outside and received. Thus, the transmitted optical signal can be monitored without cutting the optical fiber 51. Further, it is also possible to newly insert an optical signal of the same wavelength into the optical fiber 51 using this optical coupler. further,
In this embodiment, the polarization dependency can be eliminated by adding an amorphous silicon additional film to the arrayed waveguide diffraction grating 46 or by inserting a λ / 2 wavelength plate.

(Embodiment 2) FIG. 3 is a configuration diagram showing an arrayed waveguide grating type optical multiplexer / demultiplexer with a loopback optical path according to Embodiment 2 of the present invention. This array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path differs from the array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path of the first embodiment in that each output waveguide 47 and input waveguide 43 are different. An optical fiber 51 is provided in each of the optical fiber 51 and an optical fiber 51d of the optical fiber 51 through which an optical signal of wavelength λ4 propagates is provided with an arrayed waveguide grating type optical multiplexer / demultiplexer (signal processing means) 41. Is a point.

As shown in FIG. 4, the arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with a loop-back optical path further reduces the group-divided dense wavelength division multiplexed signal λ4 (or optical frequency division multiplexed signal) into smaller pieces. Demultiplexed into wavelengths λ41, λ42, ..., λ47. Further, a plurality of adjacent wavelengths λ41, λ42,.
Combining 47 optical signals (or multiple optical frequency signals)
A dense wavelength division multiplexed signal λ4 (or optical frequency division multiplexed signal) can be produced. As described above, according to the array waveguide diffraction grating type optical multiplexer / demultiplexer with the loopback optical path, the optical signal can be multiplexed or demultiplexed more densely. In addition, since a two-stage branch / insert circuit is configured, it is possible to realize dense wavelength division multiplex signal branch / insert.

(Embodiment 3) FIG. 5 is a configuration diagram showing an arrayed waveguide grating type optical multiplexer / demultiplexer with a loopback optical path according to Embodiment 3 of the present invention. The features of the arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path include an arrayed waveguide grating optical multiplexer / demultiplexer 41, a plurality of optical waveguides (loopback optical paths) 71, and a plurality of optical semiconductors. That is, the signal processing device 72 and the signal processing device 72 are formed on the same substrate 73. The flow and operation of the optical signal of the array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path are the same as those in the first embodiment.

According to this embodiment, since the input waveguide 43 and the output waveguide 47 and the optical waveguide 71 are formed on the same substrate 73, the connection step between them can be omitted. Therefore, the number of parts and the number of steps of the assembling process can be reduced, and as a result, further downsizing and higher reliability can be achieved. In this embodiment, the signal processing device 72 made of an optical semiconductor is incorporated in the arrayed waveguide grating type optical multiplexer / demultiplexer 41 made of a silica glass waveguide. If the array waveguide diffraction grating type optical multiplexer / demultiplexer 41 is manufactured using a waveguide, both can be manufactured on the same substrate 73 at the same time. Therefore, the economy can be further improved.

It should be noted that this array waveguide diffraction grating type optical multiplexer / demultiplexer with a loop-back optical path uses the same substrate 73 as the component.
Although integrated above, it can also be achieved by fixing and integrating the components by means such as laser welding, a photocurable resin such as an optical adhesive, or soldering.

(Embodiment 4) FIG. 6 is a configuration diagram showing an arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path according to Embodiment 4 of the present invention. The array waveguide diffraction grating type optical multiplexer / demultiplexer with a loop-back optical path includes a variable wavelength semiconductor laser light source 81, an intensity modulator 82, a polarization compensator 83, an input side optical fiber transmission line 6, a quartz glass , A 7 × 7 arrayed waveguide grating type optical multiplexer / demultiplexer 41, a plurality of delay optical fibers (delay means) 84, a plurality of optical signal processors (signal processing means) 85, 85,. The optical fiber transmission line 7 on the side and the light receiving element 86 are schematically constituted.

The variable wavelength semiconductor laser light source 81 can switch the wavelength of the emitted light by, for example, changing the injection current. Here, the wavelengths λ1, λ2,.
A device that outputs seven 7-wave lights was used. Further, in the arrayed waveguide grating optical multiplexer / demultiplexer 41, a predetermined wavelength emitted from the tunable semiconductor laser light source 81, for example, a wavelength λ
The signal light of i is output to the output waveguides 47j (j = a, b,...) corresponding to the wavelength λi among the plurality of output waveguides 47.
g).

The delay optical fiber 84 is provided corresponding to each transmission path between the plurality of output waveguides 47 and the plurality of input waveguides 43. The waveguide 47a is a first delay optical fiber 84.
a, the second output waveguide 47b is connected to the second input waveguide 43b through the second delay optical fiber 84b, and so on. The signal light output from each of the output waveguides 47 can be time-delayed.

Next, the operation of the arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path will be described. The wavelength λi (i
= 1, 2,..., 7) become signal light having information processed by the intensity modulator 82, respectively.
The polarization planes of the respective signal lights are matched by 3, and after passing through the optical fiber transmission line 6 on the input side, they are input to the input waveguides 43 a to 43 g of the arrayed waveguide grating optical multiplexer / demultiplexer 41. Here, for example, the signal light pulse input to the input waveguide 43a spreads by diffraction in the slab waveguide 44, and is input to a plurality of waveguides constituting the arrayed waveguide diffraction grating 46. , The light is focused by the slab waveguide 45.

At this time, the position where the diffracted light interferes, that is, the light condensing position is determined based on the phase difference generated in the arrayed waveguide diffraction grating 46, and the light condensing position differs depending on the wavelength.
For example, each optical signal pulse having a wavelength λ1 is output from an output waveguide 47a, λ2 is output from an output waveguide 47b,..., Λ7 is output from an output waveguide 47g, and so on. (J = a, b,..., G). Of these, wavelengths λi other than λ0 (i =
The optical signal pulse for which 1, 2,..., 7) is selected is a delay optical fiber 84j (j = j) connected to the output waveguide 47j.
a, b,..., g) and iτ (i = 1, 2,.
After receiving the time delay of 7), the input waveguide 4
3j (j = a, b,..., G).

Here, iτ (i =
Each of the optical signal pulses time-delayed by 1, 2,..., 7) is collectively extracted from the common output waveguide 47h together with the optical signal pulse of λ0 that is not time-delayed, and passes through the output-side optical fiber transmission line 7. After that, the light enters the light receiving element 86 and is converted into an electric signal, which is delayed information. That is, the optical signal pulse having the wavelength λi input from the input waveguide 43j is transmitted to the delay optical fiber 84j via the output waveguide 43j determined according to the wavelength. At this time, if the wavelength of the input signal light pulse is changed, for example, to λ1, λ2,..., Λ7, the demultiplexed output light pulse is output to the output waveguide 47j (j =
a, b,..., g) can be selected, and the time delay amount is set to τ, 2τ,.
It can be changed as τ.

As described above, according to the array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path of the present embodiment,
A variable wavelength semiconductor laser light source 81, an intensity modulator 82,
The polarization compensator 83, the input side optical fiber transmission line 6, the arrayed waveguide grating optical multiplexer / demultiplexer 41, the plurality of delay optical fibers 84, and the plurality of optical signal processors 85, 85,...
And the optical fiber transmission line 7 on the output side and the light receiving element 86, the amount of time delay of the optical pulse can be arbitrarily and rapidly changed.

Since the wavelength is switched using the tunable semiconductor laser light source 81, it is possible to easily switch to an arbitrary wavelength. Further, since the amount of time delay due to wavelength switching is changed by using one arrayed waveguide grating type optical multiplexer / demultiplexer 41, characteristic variations can be reduced, and manufacturing yield can be improved. Also, there is no increase in branch loss due to an increase in the delay amount.
Further, since the light passes through the arrayed waveguide grating type optical multiplexer / demultiplexer 41 twice via the delay optical fiber 84,
The band of the optical pulse becomes narrower, so that the noise light component of the optical signal spectrum can be greatly reduced.

In this embodiment, the variable wavelength semiconductor laser light source 81 is used as the variable wavelength light source. However, various light sources can be used without being limited to the variable wavelength semiconductor laser light source 81. For example, a multi-electrode distributed Bragg reflection semiconductor laser light source, a distributed feedback semiconductor laser light source,
The same operation and effect as the variable wavelength semiconductor laser light source 81 can be obtained by using a Fabry-Perot Perot type semiconductor laser light source, an external resonator type semiconductor laser light source, or the like.

The variable wavelength light source is a combination of N fixed wavelength light sources having different wavelengths and an N × 1 optical switch. Each of the N fixed wavelength light sources having different wavelengths has an optical gate switch. May be connected and combined by an N × 1 optical coupler. The former can change the wavelength by switching the N × 1 optical switch, and the latter can change the wavelength by turning on one of the optical gate switches. Further, by changing the length of the delay optical fiber 84, etc., it is possible to easily increase or decrease the variable width and the variable range of the time delay amount by changing the wavelength.

(Embodiment 5) FIG. 7 is a configuration diagram showing an arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path according to Embodiment 5 of the present invention. This array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path is different from the array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path of the fourth embodiment in that a variable wavelength semiconductor laser light source A variable wavelength optical transmitter 92 integrating the intensity modulator 82 and the intensity modulator 82;
A spherical fiber 93, an arrayed waveguide grating type optical multiplexer / demultiplexer 41, a plurality of delay optical waveguides (delay means) 94 in place of the plurality of delay optical fibers 84, and a plurality of optical signal processors (signal processing) ... means 85, 85, ... are integrated and integrated. Here, the variable wavelength optical transmitter 92
It is difficult to directly connect the optical waveguide multiplexer / demultiplexer 41 and the arrayed waveguide grating type multiplexer / demultiplexer.

As the optical signal processor 85, for example, the following ones can be appropriately used. FIG. 8 shows an optical signal processor 85 in which an optical amplifier 95 such as an optical semiconductor amplifier or a glass waveguide amplifier is incorporated in the middle of a delay optical waveguide 94. Loss of the wave device 41 and the transmission path can be compensated.

FIG. 9 shows an optical signal processor 85 which incorporates an optical gate switch 96 such as a lithium niobate (LiNbO ₃ ) optical modulator or an optical semiconductor switch in the middle of the delay optical waveguide 94. Gate switch 9
The optical signal processing can be performed by turning on or off the 6 or variable wavelength optical transmitter 92 to pass or block a part of the optical signal.

As described above, according to the arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path of the present embodiment,
On a substrate 91, a variable wavelength optical transmitter 92, a spherical fiber 93, an arrayed waveguide grating optical multiplexer / demultiplexer 41, a plurality of delay optical waveguides 94, and a plurality of optical signal processors 85 are provided. Since they are integrated, the same operation and effect as those of the array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path of the third embodiment can be obtained. Further, since the connection between the tunable wavelength semiconductor laser light source 81 and the intensity modulator 82 by the optical fiber and the connection process can be omitted, the intensity modulator 82 and the arrayed waveguide grating optical multiplexer / demultiplexer 41 can be omitted. , The polarization compensator 83 can be omitted. Therefore, it is possible to further reduce the size, the number of parts, and the number of assembly steps.

In this integration, in addition to forming each component on the same substrate as in this embodiment, each component is formed by means such as laser welding or a photo-curing resin (optical adhesive). It can also be achieved by fixing and integrating the gaps. Further, the variable wavelength optical transmitter 92 and the arrayed waveguide grating type optical multiplexer / demultiplexer 41 are configured to be coupled by the spherical fiber 93, but are not limited to the spherical fiber 93, and may be configured by appropriately using an optical coupling circuit. be able to. For example, if the spot size conversion waveguide for efficiently coupling the two is formed on the same substrate as the arrayed waveguide diffraction grating type optical multiplexer / demultiplexer 41, further economy can be achieved.

(Embodiment 6) FIG. 10 shows Embodiment 6 of the present invention.
FIG. 3 is a configuration diagram showing an arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with a loop-back optical path. This array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path is different from the array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path of the fifth embodiment in that the input waveguide 43 on the substrate 91 and the output The point that the lengths of the plurality of delay optical waveguides (delay means) 97 connected to the waveguide 47 are configured to be inversely proportional to the propagating wavelength, and the optical fiber transmission connected to the input waveguide 43 The point is that it is connected to an external semiconductor laser light source by the path 6.

Here, since the delay optical waveguide 97 is configured to be longer on the side where light of shorter wavelength propagates, the time-series optical pulse distributed in a permutation for each wavelength or the same for each wavelength. The position on the time axis can be controlled for the time-series light pulse distributed at the time. For example, compression or separation of a time-series optical pulse group on the time axis is performed.

Here, compression of the time-series light pulse group will be described. Generally, when an optical pulse propagates through an optical fiber, the width of the optical pulse is widened due to chromatic dispersion during transmission of the optical fiber, chirping of a semiconductor laser light source, and the like. Here, it is assumed that the spread optical pulse is equivalent to an optical pulse in which short optical pulse components from a short wavelength to a long wavelength are combined on a time axis. That is, FIG.
As shown in FIG. 7, the light pulse groups λN,..., Λ2, λ1 that are generated relatively faster as the wavelength becomes shorter are input.

In the array waveguide diffraction grating type optical multiplexer / demultiplexer with a loop-back optical path, the length of each of the plurality of delay optical waveguides 97 that passes after the optical pulse is demultiplexed is determined by the interval T of the optical pulse. Is set in advance so that the time delay difference τ between the adjacent delay optical waveguides is equal to the interval T, so that the long wavelength component of the optical pulse advances relatively faster than the short wavelength component. . As a result, the shorter the wavelength of the optical pulse, the longer the propagation time becomes, and the optical pulse train spread on the time axis becomes a plurality of delay optical waveguides 97 having opposite delay characteristics.
Can be compressed.

Next, separation of the time-series light pulse group will be described. For example, the multi-wavelength oscillating semiconductor laser light can be regarded as a combined light of wavelengths λ1, λ2,..., ΛN oscillating at the same time. With respect to the input of an optical pulse obtained by externally modulating the laser light, that is, an optical pulse group oscillated at the same time with wavelengths λ1, λ2,..., ΛN, the short wavelength component of the optical pulse is relatively slower than the long wavelength component. As shown in FIG. 12, the optical pulse group passes through the plurality of delay optical waveguides 97, and thus the short-wavelength component moves on the time axis in accordance with the wavelength such that the short-wavelength component advances relatively slower than the long-wavelength component. Decomposed. As a result, an optical pulse group consisting of simultaneously oscillating wavelengths λN,..., Λ2, λ1 can be separated on the time axis.

As described above, according to the array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path of the present embodiment,
The length of the plurality of delay optical waveguides 97 connecting the input waveguide 43 and the output waveguide 47 on the substrate 94 is configured to be inversely proportional to the propagating wavelength. The compressed or separated time-series light pulse group can be appropriately compressed or separated on the time axis.

(Embodiment 7) FIG. 13 shows Embodiment 7 of the present invention.
FIG. 3 is a configuration diagram showing an arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with a loop-back optical path. This array waveguide diffraction grating type optical multiplexer / demultiplexer with a loop-back optical path is different from the array waveguide diffraction grating type optical multiplexer / demultiplexer with a loop-back optical path of the first embodiment in that one signal processing device 52b is a wavelength converter. (Signal processing means) 101, output waveguides 47k and 47m are newly added to the slab waveguide 45, and the output waveguides 47k and 47m are added.
The point is that the optical fiber transmission lines 102k and 102m are newly connected to each other.

The wavelength converter 101 includes an O / E converter 103 for temporarily converting an optical signal into electricity, and an E / O converter 10 for driving a laser light source of another wavelength again based on the electrical signal.
4, but in addition to this configuration, for example, KT
Modulators using nonlinear optical crystals such as P, lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), lead molybdate (PbMoO ₄ ), tellurium dioxide (TeO ₂ ), lithium niobate, tellurite An acousto-optic modulator using a crystal material such as glass can also be used.

In the array waveguide diffraction grating type optical multiplexer / demultiplexer with a loop-back optical path, the wavelength converter 101 of the plurality of wavelength multiplexed signal lights input to the input waveguide 43h after propagating through the optical fiber transmission line 6 is used. The optical signal whose wavelength has been converted by the optical fiber is not extracted from the optical fiber transmission line 7, but is output from another optical fiber transmission line 102 via the output waveguide 47. For example, if the wavelength λ2 of the signal light split into the optical fiber 51b is converted into λ3, the optical signal having the wavelength λ3 can be transmitted to the optical fiber transmission line 102k via the output waveguide 47. Therefore, if the arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to the present embodiment is used as a node of a ring network or the like, it is possible to select a route that escapes from the ring and goes to an external node or terminal station. .

(Eighth Embodiment) FIG. 14 shows an eighth embodiment of the present invention.
FIG. 3 is a configuration diagram showing an arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with a loop-back optical path. This array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path is different from the array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path of the first embodiment in that one signal processing device 52b is an optical bistable. An element (signal processing means) 111 is provided.

The optical bistable element 111 utilizes an optical nonlinear effect of an optical semiconductor laser or the like having a saturable absorption region. One optical pulse is input to the optical bistable element 111 as shown in FIG. Then, the optical bistable element 111 is oscillated by the nonlinear optical effect. Here, when an electric reset pulse is applied to the saturable absorption region, the optical bistable element 111 changes to a non-oscillation state. in this way,
It is possible to newly generate an optical pulse that turns on the time from the input of the optical pulse serving as a trigger to the application of the electric reset pulse. Therefore, the ON state time can be arbitrarily varied.

(Embodiment 9) FIG. 16 shows Embodiment 9 of the present invention.
FIG. 3 is a configuration diagram showing an arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with a loop-back optical path. This array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path is different from the array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path of the sixth embodiment in that one slab waveguide 44 has an arrayed waveguide. The input and output ends of the diffraction grating 46 are connected, the input waveguide 43 and the output waveguide 47 are provided in the slab waveguide 44, and the optical signal processor 85 is removed from the delay optical waveguide 97. .

Here, the length of each waveguide of the delay optical waveguide 97 is configured to be longer as the waveguide on the side where the short wavelength component λs of the optical signal propagates. For this reason,
The delay optical waveguide 97 functions as a normal dispersion medium having a dispersion wavelength larger than the zero dispersion wavelength of the dispersion-shifted optical fiber whose wavelength is 1.3 μm. For example, if the wavelength is 1.5
When an optical pulse of 5 μm propagates in a 1.3 μm dispersion-shifted optical fiber, the short wavelength component λS propagates relatively faster than the long wavelength component λL because this optical fiber acts as an extraordinary dispersion medium. Therefore, the pulse width of the propagating light pulse is increased.

When the optical pulse whose pulse width is widened is input from the optical fiber transmission line 6 to the arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with a loop-back optical path, the shorter wavelength component λ S at the leading edge of the optical pulse is applied. The longer the longer wavelength component λL of the trailing edge, the faster the propagation. Therefore, the delay optical waveguide 97 functions as a normal dispersion medium having the opposite dispersion characteristic, narrowing the pulse width due to chromatic dispersion, and performing so-called dispersion compensation (equalization). On the other hand, if the length of each waveguide of the delay optical waveguide 97 is configured to be shorter as the waveguide on the side on which the short wavelength component λS of the optical signal propagates, the delay optical waveguide 97 can be formed as an extraordinary dispersion medium. Can function as For example, it suppresses (equalizes) the spread of the pulse width of an optical pulse having a wavelength smaller than the zero dispersion wavelength of the 1.3 μm dispersion-shifted optical fiber.

The function of dispersion compensation of the delay optical waveguide 97 can produce exactly the same effect as described above for an optical pulse of an arbitrary wavelength to be used if the delay amount is set according to the dispersion amount. . Further, since only one slab waveguide 44 is used, the size of the entire arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path can be reduced.

(Embodiment 10) FIG. 17 is a structural view showing an arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to Embodiment 10 of the present invention. This array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path is different from the array waveguide diffraction grating type optical multiplexer / demultiplexer with a loopback optical path of the eighth embodiment in that each output waveguide 47 and input waveguide 43 are different. The optical fibers 51a to 51d are respectively provided between the optical fibers 51a to 51d, and a node (signal processing means) 12 having a function of transmitting, amplifying, branching, and joining an optical signal to each of the optical fibers 51a to 51d.
1a to 121d are provided, and these optical fibers 51a to 51d are provided.
The point is that a 4 × 4 optical matrix switch (signal processing means) 122 is provided so as to straddle 51d.

In this embodiment, the input waveguide 4 for returning a plurality of optical signals by switching the optical matrix switch 122
By switching between 3a to 43d, the path of the optical signal can be arbitrarily selected. In this embodiment, since the input waveguide 43e is used as the input of the wavelength division multiplexed optical signal and the output waveguide 47e is used as the output, in principle, (5-1)! = 4 × 3 × 2 × 1 = 24 different routes can be arbitrarily selected.

The operation of the arrayed-waveguide grating type optical multiplexer / demultiplexer with a loop-back optical path will now be described with reference to FIG. By switching the optical matrix switch 122, for example, the output waveguide 47a is moved to the input waveguide 43b,
The output waveguide 47b is connected to the input waveguide 43a, and the output waveguide 4
7c is connected to the input waveguide 43d, and the output waveguide 47d is connected to the input waveguide 43c, so that the optical signal of the wavelength λ1 is transmitted through the node 121b-node 121c-node 121d-node 121a. Output to Similarly, an optical signal of wavelength λ2 is from node 121a to node 121b, an optical signal of wavelength λ3 is from node 121d to node 121c, and an optical signal of wavelength λ4 is from node 121c to node 121c.
The signal is output to the optical fiber transmission line 7 via each of the nodes 121b-121a-121d.

Here, each optical signal passes through one or more nodes 121 a to 121 d on the optical fiber 51 and is always output to the common optical fiber transmission line 7. On the other hand, the pilot signal light of wavelength λ0 is
22, the input waveguide 43e, the arrayed waveguide grating 46, and the output waveguide 4 without passing through the nodes 121a to 121d.
The signal is output to the optical fiber transmission line 7 via each of the transmission lines 7e.

As described above, the optical matrix switch 12
2, the output waveguides 47a to 47d
The connection between the input waveguides 43a to 43d can be changed as appropriate, and the nodes 121a to 121d passing therethrough can be arbitrarily selected. Even when only one type of wavelength is used, if the path is set by switching the optical matrix switch 122, the nodes 121a to 121
One or more of 121d can be arbitrarily selected. Also, the order of passing through these nodes 121a to 121d can be set as needed. Further, when the optical matrix switch 122 is switched at a high speed, the path through which the optical pulse passes changes over time, so that the optical matrix switch 122 can be operated as an optical memory that stores optical cells or optical packets composed of a group of optical pulses for a certain time.

[0075]

As described above, according to the first aspect of the present invention,
According to the described array waveguide diffraction grating type multiplexer / demultiplexer with a loopback optical path, an array waveguide diffraction grating type optical multiplexer / demultiplexer,
A plurality of loop-back optical paths, wherein the array waveguide
The diffraction grating type optical multiplexer / demultiplexer is composed of an arrayed waveguide diffraction grating and
Multiple input sections to which signal light is input and whether signal light is output
A plurality of output units of the same number as the plurality of input units;
Provided between the input section of the
A first slab waveguide for splitting or combining an optical signal;
A plurality of output sections and the arrayed waveguide diffraction grating.
Second slab waveguide for splitting or combining optical signals
Wherein one of the plurality of input units is external or
And an input unit for inputting an input signal light from the plurality of outputs.
One of the power units is an output for outputting an output signal light to the outside.
And the plurality of loopback optical paths are directed to the outside.
A plurality of the output sections except an output section for outputting an output signal light
And the input section for inputting an input signal light from the outside is excluded
A plurality of input units are provided corresponding to each other,
Output signal light to the outside of the plurality of output units.
The signal light from each output section except the output section
An input signal light is input from the outside of the plurality of input units.
Connected to each input unit except for the input unit
At least one of the plurality of loopback optical paths
Signal processing to the signal light propagating through this loopback optical path.
Signal processing means for processing, before input from outside
Combining the wavelength multiplexed signal light with the arrayed waveguide diffraction grating type light
The signal light is split by the
The arrayed waveguide diffraction grating again through the loopback optical path.
Input to the optical multiplexer / demultiplexer, and multiplexed.
So that the loopback optical path is
Due to the clever configuration used, multiplexing and demultiplexing can be performed in one array.
This can be performed by a waveguide grating type optical multiplexer / demultiplexer. Therefore, the wavelength characteristics of the demultiplexer and the multiplexer can be completely matched, and the production yield can be improved. Further, since the signal light passes through the optical multiplexer / demultiplexer having the same characteristic a plurality of times, the pass band of the signal light becomes narrower, and therefore, the noise spectrum component of the optical signal spectrum can be greatly reduced.

Further , among the plurality of loopback optical paths,
At least one is provided with signal processing means for performing signal processing on signal light propagating through the loopback optical path, so that signal processing required for this optical signal can be separately performed for each wavelength.

[0077]

[0078] Further, according to the loop-back optical path with an array waveguide diffraction grating type demultiplexer of claim 2, integrated with the array waveguide diffraction grating multiplexer-demultiplexer and a plurality of said loop-back optical path of Therefore, the coupling loss between the arrayed waveguide grating type optical multiplexer / demultiplexer and the plurality of loopback optical paths can be reduced, and the small and stable arrayed waveguide grating type multiplexer / demultiplexer with loopback optical path can be provided. A wave device can be realized.

[0079] Further, according to the loop-back optical path with an array waveguide diffraction grating type demultiplexer of claim 3, wherein the pilot signal light of the signal light does not pass through the loop-back optical path, from the outside The input section for inputting an input signal light
From the input to the arrayed waveguide grating optical multiplexer / demultiplexer,
Since the output section outputs the output signal light to the outside, it is possible to stabilize each signal light using the pilot signal light as a reference signal.

According to the array waveguide diffraction grating type multiplexer / demultiplexer with a loop-back optical path according to the fourth aspect , since the loop-back optical path is a delay means, the time-series light pulse is not reflected on the time axis. The position can be controlled. Therefore, control and accumulation (memory operation) such as compression and separation can be performed on the time axis with respect to the time-series optical pulse group.

As described above, the structure can be simplified, the yield can be improved and the stability can be improved.
In addition, it is possible to provide an arrayed waveguide diffraction grating type optical multiplexer / demultiplexer with a loop-back optical path which does not increase the branch loss and can prevent the deterioration of the S / N ratio.

Further, various functions such as an optical add / drop circuit, an optical delay line memory, and an optical delay equalizer, which are extremely useful for constructing an optical transmission system, an optical switching system, etc., can be realized with the same circuit configuration. Therefore, excellent effects not obtained in the conventional optical device can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to a first embodiment of the present invention.

FIGS. 2A and 2B are configuration diagrams illustrating examples of a signal processing device of an arrayed waveguide grating type optical multiplexer / demultiplexer with a loopback optical path according to the first embodiment of the present invention; FIG. 2A illustrates an O / E converter and an E / E converter; An optical pulse reproduction processing device including an / O converter 54 and a waveform shaping circuit, (b) is an optical amplifier, (c) is a signal processing device having a 2 × 2 optical switch, and (d) is an optical filter. .

FIG. 3 is a configuration diagram illustrating an arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to a second embodiment of the present invention.

FIG. 4 is a principle diagram showing how a dense wavelength-division multiplexed signal subjected to group branching is further finely branched.

FIG. 5 is a configuration diagram illustrating an arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to a third embodiment of the present invention.

FIG. 6 is a configuration diagram showing an arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to a fourth embodiment of the present invention.

FIG. 7 is a configuration diagram illustrating an arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to a fifth embodiment of the present invention.

FIG. 8 is a configuration diagram showing an example in which a signal processing device of an arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to a fifth embodiment of the present invention is an optical amplifier.

FIG. 9 is a configuration diagram showing an example in which a signal processing device of an arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to a fifth embodiment of the present invention is an optical gate switch.

FIG. 10 is a configuration diagram illustrating an arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to a sixth embodiment of the present invention.

FIG. 11 is an explanatory diagram illustrating a state in which a time-series optical pulse group is compressed.

FIG. 12 is an explanatory diagram showing a state in which a time-series optical pulse group is separated.

FIG. 13 is a configuration diagram showing an arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to a seventh embodiment of the present invention.

FIG. 14 is a configuration diagram showing an arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to an eighth embodiment of the present invention.

FIG. 15 is a diagram showing each waveform of an optical pulse.

FIG. 16 is a configuration diagram showing an arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to a ninth embodiment of the present invention.

FIG. 17 is a configuration diagram showing an arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to a tenth embodiment of the present invention.

FIG. 18 is a diagram showing input / output states of optical signals of an arrayed waveguide grating optical multiplexer / demultiplexer with a loopback optical path according to a tenth embodiment of the present invention.

FIG. 19 is a configuration diagram showing a conventional optical add / drop circuit.

FIG. 20 is a configuration diagram showing another conventional optical add / drop circuit.

FIG. 21 is a configuration diagram showing a conventional parallel arrangement type optical delay line memory.

FIG. 22 is a configuration diagram showing a conventional loop-loop optical delay line memory.

FIG. 23 is a configuration diagram showing a conventional arrayed waveguide diffraction grating type optical multiplexer / demultiplexer.

[Explanation of symbols]

 6, 7 Optical fiber transmission line 41 Array waveguide diffraction grating type optical multiplexer / demultiplexer 43a-43h Input waveguide 44 Slab waveguide 46 Array waveguide diffraction grating 47a-47h, 47k, 47m Output waveguide 51a-51g Optical fiber (Loopback optical path) 52a to 52g Signal processing device 53 O / E converter 54 E / O converter 57 Optical amplifier 58 2 × 2 optical switch 61 to 64 port 65 Optical filter 71 Optical waveguide (Loopback optical path) 72 Signal processing Apparatus 73 Substrate 81 Variable wavelength semiconductor laser light source 82 Intensity modulator 83 Polarization compensator 84 Delay optical fiber (Delay means) 85 Optical signal processor (Signal processing means) 86 Light receiving element 91 Substrate 92 Intensity modulator 93 Pointed fiber 94 delay optical waveguide (delay means) 97 delay optical waveguide (delay means) 101 wavelength converter Signal processing means) 102k, 102m Optical fiber transmission line 103 O / E converter 104 E / O converter 111 Optical bistable element (signal processing means) 121a to 121d Node (signal processing means) 122 Optical matrix switch (signal processing means) ) Λ0 pilot signal light λ1, λ2, ..., λ7 signal light

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Inoue Nippon Telegraph and Telephone Corporation, 1-6, Uchisaiwaicho, Chiyoda-ku, Tokyo (56) References JP-A-64-20506 (JP, A) JP-A-Hei 6-3556 (JP, A) JP-A-2-244105 (JP, A) JP-A-6-194534 (JP, A) US Pat. No. 5,136,671 (US, A) US Pat. No. 4,908,933 (US, A) Hiroshi Takahashi et. al. , C-230, 1992 IEICE Spring Conference Proceedings, March 15, 1992, [Part 4] Communications and Electronics, p. 4-272 (58) Field surveyed (Int.Cl. ⁷ , DB name) G02B 6/12-6/14 G02B 6/28-6/293 G02F 1/00-1/035 G02F 1/29-3 / 02 H01S 3/10 H01S 5/022-5/026 H04B 10/00-10/18 H04J 14/00-14/02

Claims (4)

(57) [Claims] 1. A method for demultiplexing and multiplexing wavelength multiplexed signal light.
Arrayed Waveguide Diffraction Grating with Loopback Optical Path
An optical multiplexer / demultiplexer having an arrayed waveguide grating and a plurality of loop bars.
An array waveguide diffraction grating type optical multiplexer / demultiplexer, comprising: an array waveguide diffraction grating; and a plurality of input ports to which signal light is input.
Power units, the number of which is equal to the number of the input units, from which the signal light is output
A plurality of outputs, the plurality of inputs and the array waveguide
For splitting or combining optical signals provided between
A first slab waveguide, the plurality of output sections, and the array
B) an optical signal provided between the
A second slab waveguide for multiplexing , wherein one of the plurality of input sections receives an external input signal light.
And one of the plurality of output units outputs an output signal light to the outside.
An output unit for outputting, and the plurality of loop-back optical paths are provided in front of a plurality of output units excluding the output unit for outputting the output signal light to the outside.
And an input for inputting an input signal light from the outside.
Provided for each of the plurality of input units except for the unit.
Output signal to the outside of the plurality of output units.
The signal light from each output section except the output section that outputs light
Input signal light from the outside of the plurality of corresponding input sections
Input to each input unit except for the input unit
Connected to at least one of the plurality of loopback optical paths.
Is used to process the signal light propagating through this loopback optical path.
Signal processing means for applying the wavelength multiplexed signal light input from the outside to the array waveguide.
Demultiplexed by a path grating optical multiplexer / demultiplexer.
A plurality of signal lights are again transmitted through each loopback optical path.
Ray-waveguide grating type optical multiplexer / demultiplexer
It should be configured to output to the outside as output signal light.
Array waveguide diffractometer with loopback optical path characterized by
Sub type optical multiplexer / demultiplexer. 2. An array with a loop-back optical path according to claim 1.
A waveguide diffraction grating type optical multiplexer / demultiplexer , wherein the array waveguide diffraction grating type optical multiplexer / demultiplexer and a plurality of the loopback optical paths are integrated.
Waveguide grating type optical multiplexer / demultiplexer. 3. The loop-back light according to claim 1 or 2.
In the arrayed waveguide waveguide grating type optical multiplexer / demultiplexer, the pilot signal light of the signal light does not pass through the loop-back light path, and the input signal light is input from the outside.
The array waveguide diffraction grating from the input unit for inputting
Input to the optical multiplexer / demultiplexer before outputting the output signal light to the outside
Characterized in that it is configured to output from the output unit
Array waveguide diffraction grating type optical multiplexing / demultiplexing with loopback optical path
vessel. 4. A loop bag according to claim 1, 2 or 3.
In the array waveguide diffraction grating type optical multiplexer / demultiplexer with an optical path, the loopback optical path is a delay unit.
Array Waveguide Diffraction Grating Type Optical Combining with Loopback Optical Path
Waver.